Late May heat in NorCal...how will early heat affect grapes?

I have been seeing a couple of posts indicating high 90s to 100 degrees in Sonoma. It’s late May for crying out loud! I would imagine that high heat is atypical for this early in the season. How might a few days of high 90s affect grapes and vines, if at all, this early in the growing season?

And then followed by possible rain?

You may want to post in the ITB thread for 2020 weather for Western US

Check out “Cellar Rats” under the Board Index and look for topic: 2020 West Coast Weather and Farming Thread

Thanks, Guys. Will redirect.